Improved planarization process for producing carriers with low step height

ABSTRACT

A process to reduce step heights in planarization of thin film carriers in an encapsulation system. The improvements include using an adhesive tape having a thinner adhesive thickness and a stiffer tape for the film sealing the encapsulant on the carrier to result in a low step height surface transition between the carrier and the cured encapsulant. The composition of the encapsulant is modified to reduce the shrinkage upon curing of the encapsulant. The encapsulant may include an absorbent that absorbs the irradiation and cause the top surface to harden first compared to the bulk of the encapsulant, and/or a gas-emitting additive that creates gaseous products that expand upon irradiation to thereby reduce the shrinkage of the encapsulant upon curing. Alternatively, irradiation at very low incidence angle relative to the top surface of the encapsulant causes the top surface to harden before the bulk of the encapsulant.

RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 10/109,929, filed Mar. 29, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to preparing thin films for etchpatterning. More specifically, the invention relates to preparing thinfilm substrates and encapsulating material for etch patterning to formthe air-bearing surface of a slider.

2. Description of Related Art

Conventional magnetic disk drives are information storage devices thatutilize at least one rotatable magnetic media disk with concentric datatracks. They also utilize a read/write transducer for reading andwriting data on the various tracks or separate read and writetransducers as in the magnetoresistive and giant magnetoresistive headsthat have become the trend in the data storage industry as a means ofimproving data storage density. Disk drives generally also have an airbearing slider for holding the transducer adjacent to the trackgenerally in a flying mode above the media, a suspension for resilientlyholding the slider and the transducer over the data tracks, and apositioning actuator connected to the suspension for moving thetransducer across the media to the desired data track and maintainingthe transducer over the data track during a read or a write operation.

The recording density of a magnetic disk drive is limited by thedistance between the transducer and the magnetic media. One goal of airbearing slider design is to “fly” a slider as closely as possible to amagnetic medium while avoiding physical impact with the medium. Smallerspacing, or “fly heights,” are desired so that the transducer candistinguish between the magnetic fields emanating from closely spacedregions on the disk.

In addition to achieving a small average spacing between the disk andthe transducer, it is also critical that a slider fly at a relativelyconstant height. The large variety of conditions that transducersexperience during the normal operation of a disk drive can makeconstancy of fly height anything but a given. If the flying height isnot constant, the data transfer between the transducer and the recordingmedium may be adversely affected.

The manner in which a slider is manufactured and the material the slideris fabricated from can affect fly height. Preferably variations in thephysical characteristics of the slider, e.g. due to manufacturingtolerances, should not substantially alter the flying height of theslider. If this result is not achieved, the slider's nominal fly heightmust be increased to compensate for variations between sliders.

In the past, the processes for defining air bearing surfaces includedusing a dry-film resist as the etch mask for a single etch step.However, most current air-bearing surface designs use two or more etchsteps to provide lower fly heights and better fly height control.Moreover, slider air-bearing designs for lower fly height mayincorporate small pads or other features that are difficult to patternusing dry film resists. Liquid resists have much better resolutioncapability and are preferred for forming the smaller features of theair-bearing design. To process multiple etch designs, an ion millingstep and a reactive ion etching step may be used for either of bothsteps. At certain row spacings the ion milling etch results inredeposited materials being formed on the sides of the rows, whichcannot be removed. In addition, the etch profiles obtained after ionmilling and reactive ion etching steps have shallow wall profiles whichmake inspection difficult and affect the flying characteristics of theslider.

U.S. Pat. No. 5,617,273, to Carr, et al. provides the fabrication of aslider in which the head read and write elements protrude out from theair-bearing surface of the slider to allow for closer proximity to thedisk. The problem with this design is that the protective carbonovercoat of the slider is removed during the early functioning of thedrive, leaving the elements exposed to the drive environment. As aresult, corrosion of the elements can occur, which shortens the lifetimeof the drive. Corrosion is a leading cause of lower yields for drivecomponents and has become a huge problem as carbon overcoat layers arebecoming thinner.

U.S. Pat. No. 5,509,554 to Samuelson, et al. provides the small padsthat are necessary for lower fly heights by using imaging methods inwhich the small pads are attached to larger sacrificial structures. Thesacrificial structures must then be removed during the subsequent deepetch step. As a result, all of the areas of the slider that contain thesacrificial structures must be milled to the deepest etch depth. Thisapproach places restrictions on the ABS designers in terms of theplacement of deep etch pockets. Many of today's ABS designs could not befabricated if the methods of this patent were used.

U.S. Pat. No. 5,516,430 to Hussinger provides a planarization procedurethat uses alignment fixtures to accommodate liquid resist application. Afilled thermoplastic material is then place don the rows with asubstrate on top. The substrate is heated to 400-500° F., causing theencapsulating material (or encapsulant) to melt and flow into the gasbetween the rows. The heating process is controlled by maintaining thealignment fixture near ambient temperature to avoid the encapsulant fromsticking to the fixture. Sufficient heat is applied to melt the materialnear the air-bearing surface (ABS) that may contain thermally sensitivetransducers.

A disadvantage of using the Hussinger process is the potential forseepage of material onto the air-bearing surface of the slider. Thepresence of tapers at the leading edge of the slider provides a conduitby which the material can reach the ABS. Contamination of the ABS alsocauses photoresist imaging and adhesion problems.

Another problem with the Hussinger procedure is the need for pins toisolate the rows and provide constant gaps between rows. Once theplanarization method is carried out, the pins are removed, causing holesto exist in the encapsulated carrier. These holes or defects will thenaffect the uniformity of the resist coating. In the areas of the carrierclose to the void and extending in a radial direction outward from thevoid, there will be severe effects on resist thickness. After patterningand etch, the resist thickness variation will be translated into the ABSpattern in the form of etch profile variation, which will causedifferences in fly height. Large differences in fly height areunacceptable because of the effect on head performance; thus, theseheads will be discarded, lowering yield. The holes will also contributeto yield loss since sliders near holes will be subjected to redepositionduring etch steps. Furthermore, the high temperature requirement forthis procedure (400-500° F.) may preclude use of certain thermallysensitive transducers such as giant magnetoresistive sensors, which areused to produce higher density magnetic storage products.

In response to these disadvantages, U.S. Pat. No. 5,932,113 to Kurdi, etal. (hereinafter referred to as the “Kurdi patent”) provides a processfor preparing an air-bearing slider that uses an adhesive film made byNikko Dento and an acrylic encapsulating fluid to fill the recessesbetween the rows during etching. The Kurdi method attempts to eliminateredeposition contamination during etching and to protect the activetransducer devices from handling damage. According to the Kurdi patent,thin films may comprise a transducer-laden air-bearing surface (ABS). Anadhesive film is then generally applied to the ABS side of the thinfilms. A fluid is then deposited in the recess, which is held in therecess by the adhesive film. The fluid may then be cured and theadhesive film removed to provide a planar surface. The ABS side of therow may then be coated with an etch mask, the etch mask developed andair bearing surface patterned.

The Kurdi patent discloses the use of Nitto Denko dicing tape and anacrylic encapsulation fluid to partially fill the gaps between rows.However, implementation of the Kurdi patent may give rise to stepheights in the planar surface, resulting in large variations in theliquid resist coating thickness, which are problematic for theair-bearing surface patterning process. It could produce indentations ofabout 30 microns from the air-bearing surface in the gaps that separaterows. Several factors contribute to the formation of such indentations.First, it is the flexibility of the tape that causes the tape to sinkdue partly to its own weight and lack of stiffness. Second, theshrinkage of the encapsulant also contributes to the increase in thedepth of the indentations. These indentations result in step heights ofabout 30 microns from the air-bearing surface. The relatively large stepheights created by the Kurdi process would affect uniformity of thethickness of the resist coating during the etching process.

It is therefore desirable to create methods that provide thin films withimproved planarization, and that overcomes the drawbacks in the priorart.

SUMMARY OF THE INVENTION

This invention provides a method to improve the planarization of thinfilms on a carrier in an encapsulation process to prepare a planarsurface for etching. It is the object of this invention to reduce thestep heights over the planar surface. To achieve this objective, thisinvention utilizes one or more of the following methods: (a) changingthe tapes used in the existing processes; (b) modifying the compositionof the encapsulating materials (“encapsulant”) used in existingprocesses; and (c) adjusting the irradiation conditions in which theair-bearing surface is prepared.

The invention provides a different adhesive tape to be used during theplanarization process. The contribution to the increase of step heightas a result of the tape can be minimized when a tape having a thinneradhesive layer is used. Further, the invention replaces the compliantPVC backing the tapes used in existing processes with a stiffer materialbacking such as polyethylene terephthalate, or polyethylene orpolyethylene copolymers.

Another cause for the creation of the step height is the shrinkage ofthe acrylic encapsulant during the irradiation process. The inventionprovides two approaches with respect to modifying the composition of theencapsulant in order to reduce the step height caused by the shrinkage.First, the preferred approach is to include absorbents in theformulation of the encapsulant. The absorbents absorb the irradiation,thus reducing the curing effect. The presence of the absorbents alsocauses the top surface, which is the first surface of the encapsulant tobe exposed to the UV light, to harden first compared to the bulk of theencapsulant. When the top surface hardens first and thus is fixated inits position, the contribution to the increase in step height as aresult of the further shrinkage in the bulk of the encapsulant below thetop surface will be minimized. The absorbent can be a bleachable orunbleachable dye (such as Curcumin), or it can even be photo-initiators.The second approach is to add a gas-emitting additive into theencapsulant, which will be converted into gaseous products uponirradiation. During the radiation, the additive will expand and formbubbles within the encapsulant, thus reducing the shrinkage of theencapsulant in volume.

Finally, the invention also describes modification of the irradiationconditions, which can reduce the step height as a result of theshrinkage of the encapsulant. Specifically, by irradiating at very lowincidence angle relative to the top surface of the encapsulant, the topsurface of the encapsulant will be hardened before the bulk of theencapsulant. After the hardening of the top surface of the encapsulant,irradiation at the normal incidence angle can be used to cure the bulkof the encapsulant.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and advantages of theinvention, as well as the preferred mode of use, reference should bemade to the following detailed description read in conjunction with theaccompanying drawings. In the following drawings, like referencenumerals designate like or similar parts throughout the drawings.

FIG. 1 is an exploded perspective view of an exemplary hard driveassembly including a slider.

FIG. 2A is a bottom plan view of an exemplary slider.

FIG. 2B is a partial cutaway view along axis B-B of the slider depictedin FIG. 2A.

FIG. 3 is a perspective view of a row carrier having rows bondedthereto, air bearing surface side up, according to the invention.

FIG. 4 is a perspective view of the row carrier depicted in FIG. 3additionally comprising an adhesive film laminated to the ABS side ofthe rows.

FIG. 5 is a cutaway top plan view of the row carrier depicted in FIG. 4showing introduction of a fluid into the cavities.

FIG. 6 is a perspective view of the row carrier depicted in FIG. 5, withthe adhesion film removed.

FIG. 7 is a sectional view of the row carrier along line 7-7 in FIG. 5.

FIG. 8 is a view of the row carrier in FIG. 7 after the adhesive film isremoved.

FIG. 9 is an enlarged view of the section 9 in FIG. 8.

FIG. 10 is a table with planarization step height data for modifiedencapsulants and tapes.

FIG. 11 is a table with concentration, mode of action, and wavelengthdata for modified encapsulants.

FIG. 12 is a view of the chemical structure of DMA (DiazoMeldrums Acid).

FIG. 13 is a view of the chemical structure of BAMC(2,6-Bis-(4-azidobenzylidene)-4-methylcyclohexanone).

FIG. 14 is a view of the chemical structure of Curcumin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention is described in a preferred embodiment in the followingdescription with reference to the figures. While this invention isdescribed in terms of the best mode for achieving this invention'sobjectives, it will be appreciated by those skilled in the art thatvariations may be accomplished in view of these teachings withoutdeviating from the spirit or scope of the invention.

The present invention will be described in reference to theplanarization of thin films on a carrier in an encapsulation process toprepare a planar surface for etching air bearing surface. However, theplanarization process of the present invention is also applicable topreparing planar surfaces for other purposes.

U.S. Pat. No. 5,932,113 to Kurdi, et al. (i.e., the “Kurdi patent”),“Low Temperature Encapsulation System,” describes an encapsulationprocess for preparing the air-bearing surface for etch-patterning,including the use of adhesive tapes and encapsulating materials. Thispatent is fully incorporated by reference herein.

This invention improves on the methodology described in the Kurdi patentby (a) changing the adhesive tapes used; (b) modifying the compositionof the encapsulating materials; and (c) adjusting the irradiationconditions, in which the thin film is exposed. The novel improvementclaimed in this patent is in the following detailed description, whichillustrates a method for preparing the air-bearing surface of a slidermodified from the process disclosed in the Kurdi patent.

Generally the method of the invention may be used to pattern any sliderused in the hard drive assembly (HDA) in computing systems common in theindustry.

As background, an exemplary HDA may be seen in FIG. 1, which is anexploded view of a disk drive 100. The disk drive 100 includes a housing112 and a housing cover 114, which after assembly is mounted within aframe 116. Mounted within the housing is a spindle shaft 122. Rotatablyattached to the spindle shaft 122 are a number of disks 124. In FIG. 1,eight disks 124 are attached to the spindle shaft 122 in spaced apartrelation. The disks 124 rotate on spindle shaft 122, which is powered bya motor.

Information is written on or read from the disks 124 by thin film headsor magnetic transducers, which are supported by sliders 126. Preferably,sliders in accordance with the invention are coupled to suspensions orload springs 128. The load springs 128 are attached to separate arms 130on an E block or comb 132. The E block or comb 132 is attached at oneend of an actuator arm assembly 136. The actuator arm assembly 136 isrotatably attached within the housing 112 on an actuator shaft 138.

To facilitate the read/write operations of the hard drive assembly,slider design can be intricate, to ensure correct and constant flyheight in varying conditions. To fulfill the intended purpose of theslider, it is often patterned with various reliefs and protrusions toenhance aerodynamic character. For example, FIGS. 2A-2B illustrate aslider design 200 as disclosed in U.S. Pat. No. 5,404,256 issued Apr. 4,1995 to James W. White, entitled “Transverse and Negative PressureContour Gas Bearing Slider,” and which is incorporated by referenceherein. The slider illustrated in FIGS. 2A-2B is designed to provideuniform and controllable fly height through a range of skew angles.

In FIGS. 2A-2B, traverse pressure contour (TPC) pads 222 are defined bya face 234 for creating a gas bearing effect, a generally U-shaped TPCsection 228 including a constant depth step bearing along each side edge236 of the face 234 and a constant depth step along the leading edge 238forming a converging compression inlet 232. Thus, the gas bearingcontour of the TPC pad 222 is defined by two parallel planes created bytwo different etch steps.

A negative pressure pad 226 is defined by a substantially planarsurface, which contains a recess 240 open at the trailing end 225. Thenegative pressure pad 226 may further include one or more bearing faces242 at a height approximately that of the faces 234 of the TPC pads 222for creating a gas bearing effect. Recess 240 is open along the trailingedge 241; that is, trailing edge 241 is substantially ambient. Theambient pressure reservoir 230 defines a cavity 244 having a depth andconfiguration sufficient to maintain substantial ambient pressure in thecavity during movement of the disk. Further, ambient pressure reservoir230 includes a non-tapered (non-stepped, non-convex) inlet along leadingedge 223 so as to inhibit generation of gas bearing effects created bycompression of inlet gas.

As can be seen, the patterning of the air-bearing surface shown in FIGS.2A and 2B can be very intricate. The processes of the invention may beused to create the patterning in the air-bearing surface of this sliderwith reduced redeposition and finer patterning.

The process of the invention may be used to pattern the exemplaryair-bearing surface (ABS) of the slider shown in FIGS. 2A and 2B. Inaccordance with the invention, a standard row carrier 10 may be used, asseen in FIG. 3. Rows 12 of thin film ABS material may be affixed to therow carrier 10 through any means known to those skilled in the art. Inthe context of the present invention, a “thin film” may have anyappropriate thickness for the intended end-use application, such astransducer-laden sliders which are initially formed as rows having athickness of about 300 to 500 microns. The distance between the rows 12may range from about 300 to 1000 microns and can be as small as about100 microns or less. The means of attaching the rows 12 includesadhesives that are compatible with other laminates and adhesives used inthis invention. In the context of this invention, compatible means thatthe materials used in the invention, when in contact with each other,function independently and do not affect the function of the othermaterial.

Generally, the rows 12 are attached with the air bearing surface (ABS)14 side up to allow for the eventual patterning of the ABS side 14.Referring to FIG. 4, an adhesive film 16 is then deposited over the ABSside 14 of the rows 12. The film 16 functions to enclose the cavities orrecesses 18 between the rows 12, which are raised in relationship to therecess 18. The film 16 also protects the ABS side 14 from contamination.The film 16 may comprise any composition suitable to enclose therecesses 18 on a carrier 10 and also withstand further processing inaccordance with the invention. The depth of recesses 18 depends upon thethicknesses of the thin film rows, generally about 100 to 300 microns.

The adhesive film 16 is generally applied at temperatures ranging fromabout 25-30° C. and preferably about 25° C. The pressure of applicationmay range from about 10 lbs/cm² to 50 lbs/cm² and preferably is about 25lbs/cm². Generally, the film 16 comprises a laminate of an adhesivelayer and a substrate.

According to one aspect of the invention, since the thickness of theadhesive layer of the film 16 contributes to the step height due to theindentation of the rows into the adhesive layer, improvements can bemade by using a tape with a thinner adhesive layer and stiffer tape.With the current technology available, the practical limitation foraverage adhesive thickness is 4 microns, but may be as thin as 2microns. This limit is not imposed by the planarization process itselfbut rather by the availability of reliable tape having uniform adhesivethickness. It is possible to use this process with an adhesive thicknessof 2 microns, as disclosed in the Kurdi patent, but at some point it mayfail because the protection of the rows would break down andencapsulation fluid would leak onto the surface of the rows. Further,adhesive film with 2 micron average adhesive thickness means that someareas of the film may have no adhesive. It has been found that a4-micron average adhesive thickness would result in complete adhesivecoverage. In addition to the thinner adhesive thickness, a stiffmaterial for the tape substrate such as PET (Polyethyleneterephthalate), or polyethylene or polyethylene copolymers is preferred.The net result is that step height otherwise caused by the indentationsinto the adhesive film is reduced.

Commercially available adhesive films include 3M 6670, which is a PETbased film having a 4-5 micron thick adhesive layer, a 35-40 micronthick PET flexible substrate and 70 gm/mm of adhesion. The combinationof the 3M 6670 tape and the prior art acrylic encapsulant as practicedby the method of the Kurdi patent gave a result in which step heightsare inconsistent, range from 5 to 60 microns over the area ofplanarization. This result suggests that while step heights may reducein some areas, step heights may also increase in other areas. However,as discussed below, consistent improved step heights can be achieved bycombining modified encapsulant with the 3M 6670 tape.

Once the film 16 is put in place, an encapsulant fluid 20 may beinjected or drawn into the recesses 18 between the rows 12, as seen inFIG. 5. The row carrier 10 with the fluid 20 can also be seen in thesectional view in FIG. 7. The encapsulant fluid 20 functions to fill therecesses 18 and, once cured, to planarize the rows 12 on the carrier 10.The encapsulant fluid may be selected from the group consisting of athiol-ene composition, an acrylic composition, an epoxy composition, andmixture thereof, as referenced in the Kurdi Patent that had beenincorporated by reference herein. Examples of encapsulant fluid 20include Star Technology UV Cure Adhesive M425-1. Additionally, bybringing the level of fluid 20 to substantially the same level as therows 12 positioned on the carrier 10, a planar landscape is formedacross the surface of the carrier 10 in FIG. 6.

According to a second aspect of the invention, in order to reduce thestep height, modification of the encapsulant fluid is recommended. Theinvention provides the solution of adding either an absorbing component(dye), a gas-emitting material, or both, to the encapsulant fluid 20disposed between the rows 12 of the sliders 126 positioned on asubstrate surface to provide a level surface for subsequentphotolithography. Adding the dye absorbs light reduces shrinkage of theencapsulant fluid upon irradiation, and adding the gas-emitting materialcreates gas bubbles that increase the volume of the encapsulant uponirradiation, thereby compensating the shrinkage caused by theirradiation.

Generally, the acrylic encapsulant shrinks upon curing by 3-5% involume, which accounts for the majority of the step height. Thepreferred approach in modifying the encapsulant fluid to reduce the stepheight problem is to add an absorbing component in the formulation. Thiscauses the encapsulant to cure initially at the top surface, followed bycuring of the bulk of the film. By hardening the top surface first,further shrinkage is confined to the lower portion of the encapsulant,near the substrate, and step height is not adversely affected. Theultraviolet light-absorbing material can be a bleachable dye, anunbleachable dye, or simply more of the photo-initiator. By adding 0.15%by weight of an unbleachable dye (Curcumin, see FIG. 14) to the acrylicencapsulant, the step height for the Nitto Denko V8S process is reducedfrom 30 to 10 microns, as seen in FIG. 10, which has planarization stepheight data for modified encapsulants and tapes.

A second approach to improving the encapsulant fluid 20 utilizes theaddition of a gas-emitting component designed to alleviate the effectsof acrylic crosslinking. These are organic or organometallic additives,which upon irradiation are converted to gaseous products. The additionof this organic material causes expansion, thus an increase in thevolume of the encapsulant. An example is DiazoMeldrums Acid (DMA, seeFIG. 12), which converts to nitrogen and carbon monoxide and dioxidephotochemically. With the addition of 0.1% by weight of DMA, the stepheight is reduced from 30 to 18 microns for the standard Nitto Denkoprocess, as seen in FIG. 10.

As shown in FIG. 10, it is demonstrated that better results are obtainedwhen the tape with thin adhesive layer and stiff backing is combinedwith the modified encapsulant fluid (i.e., DMA, BAMC, and Curcuminadditives). FIG. 10 demonstrates the difference in step height whendifferent tapes for different modified acrylic encapsulants of varyingconcentrations are used. Comparing the 3M 6670 tape to the Nitto DenkoV8-S tape, which was recommended in the Kurdi patent, it is shown thatthe step height is reduced by about 70-80% when the 3M 6670 tape is usedfor modified encapsulant. In some cases, the step height is reduced to 2microns from about 30 microns when modification is made to the tape andto the encapsulant fluid. The preferred range of concentrations of theadditives in the encapsulants is 0.05%-0.15% by weight for each of DMA,BAMC and Curcumin, with a preferred range of 0.1%-0.12%.

FIG. 11 lists a few recommended additives with recommendedconcentrations and wavelengths of light commonly used in curing tools.The first additive is 0.05 to 0.15% by weight of Curcumin, which absorbsradiation (see also FIGS. 12-14). The second additive is 0.05 to 0.15%by weight of BAMC (2,6-Bis(4-azidobenzylidene)-4-methylcyclohexanone),which absorbs radiation as well as emitting gas upon radiation. Finally,0.1% by weight of DMA, which primarily emits gas upon radiation. If theconcentration of absorption additive (Curcumin or BAMC) is too low,shrinkage at the top surface will occur, resulting in unacceptable stepheights. If the concentration is too high, complete cure of the fillermaterial will be difficult.

Finally, the modified fluid 20 is cured by exposure to ultravioletirradiation through the adhesive film 16, which converts the fluid 20 toa solid encapsulant, resistant to photoresist solvent and developers. Asshown in FIGS. 6 and 8, the removal of the adhesive film 16 gives anearly planarized carrier 10 with the cured fluid 20′ and filledrecesses 18 and rows 12, which are produced by a method that is done atambient temperature and with protection of the ABS surface 14 by theadhesive film 16.

According to a third aspect of the invention, modification ofirradiation conditions is implemented. Effects similar to the dyedencapsulant can be obtained by changing the configuration of theirradiation system. By irradiating first at very low incidence angles,referring to light coming from nearly a horizontal direction relative tothe carrier, the surface of the encapsulant is hardened initially by thegradient of shrinkage that is created. The low incidence angle ofirradiation can be achieved by curing at an angle, which is between 0and 25 degrees, while maintaining the carrier in a configuration withrows perpendicular to the direction of incident radiation. Followingthis, the bulk of the film is cured with normal incidence irradiation(at 90 degrees). Using this approach with 3M 6670 tape, carriers withstep heights ranging from 3-7 microns can be obtained. Combining thislow incidence angle of irradiation with the modified 3M 6670 tape andthe “standard” (i.e., Kurdi patent method) encapsulent results in stepheights ranging from 5-10 microns. It is to be noted that the lowincidence angle of irradiation is not limited to this combination, butother combinations with modified encapsulents can be implemented aswell.

After encapsulation, the row carrier 10 is marked, the etch mask isdeveloped, and the ABS side 14 of the rows 12 is patterned.

While the invention has been particularly shown and described withreference to the preferred embodiments, it will be understood by thoseskilled in the art that various changes in form and detail may be madewithout departing from the spirit, scope, and teaching of the invention.Accordingly, the disclosed invention is to be considered merely asillustrative and limited in scope only as specified in the appendedclaims.

1. A method of processing a thin film surface, said thin film surfacecomprising at least one raised portion bordered by at least one adjacentrecess, said method comprising: applying an adhesive film to said raisedportion; depositioning a fluid encapsulant into said recess, saidencapsulant held in said recess by said film, said encapsulant comprisesan irradiation activated gas-emitting material and an irradiationabsorbing material; and irradiating and curing said encapsulant.
 2. Themethod as in claim 1, wherein said irradiation absorbing material ispresent in an effective amount to cause the surface of the encapsulantexposed to irradiation to harden before the remaining bulk of theencapsulant for reducing shrinkage of the encapsulant upon curing;wherein said gas-emitting material is present in an effective amount toform bubbles within the encapsulant for reducing shrinkage of theencapsulant during the curing thereof.
 3. The method as in claim 2,wherein said irradiation absorbing material comprises at least one of ableachable dye, unbleachable dye and photo-initiator.
 4. The method asin claim 3, wherein said unbleachable dye comprises Curcumin.
 5. Themethod as in claim 2, wherein the irradiation absorbing material isadded in the amount of 0.05 to 0.15% by weight.
 6. The method as inclaim 1, wherein said irradiation absorbing material comprises BAMC(2,6-Bis(4-azidobenzylidene)-4-methylcyclohexanone).
 7. The method as inclaim 6, wherein the BAMC is added in the amount of 0.05 to 0.15% byweight.
 8. The method as in claim 1, wherein said gas emitting materialcomprises at least one of organic and organometallic materials.
 9. Themethod as in claim 8, wherein said gas-emitting material comprises DMA(DiazoMeldrums Acid).
 10. The method as in claim 9, wherein the DMA isadded in the amount of 0.05 to 0.15% by weight.
 11. The method as inclaim 8, wherein said gas emitting material comprises BAMC(2,6-Bis(4-azidobenzylidene)-4-methylcyclohexanone).
 12. The method asin claim 1, wherein said adhesive film comprises a thin adhesive layerhaving a substantially 2 to 4 micron adhesive thickness and a stiffsubstrate that comprises at least one of PET (Polyethyleneterephthalate), polyethylene and polyethylene copolymers.
 13. The methodas in claim 1, wherein said adhesive film comprises about a 4 to 5micron thick adhesive layer and about a 35 to 40 micron thick PET(Polyethylene terephthalate) substrate.
 14. The method as in claim 1,wherein said encapsulant is selected from the group consisting of athiol-ene composition, an acrylic composition, an epoxy composition, andmixtures thereof.
 15. The method as in claim 1, further comprising thesteps of: coating said thin film surface with an etch mask; developingsaid etch mask; and etch patterning said thin film surface.
 16. A methodas in claim 1, wherein said irradiating step comprises the step ofirradiating at a first incidence angle relative to the surface of saidencapsulant such that the surface of the encapsulant exposed toirradiation hardens before the remaining bulk of the encapsulant.
 17. Amethod of processing a thin film surface, said thin film surfacecomprising at least one raised portion bordered by at least one adjacentrecess, said method comprising: applying an adhesive film to said raisedportion, said adhesive film having a stiff substrate that comprises PET(Polyethylene terephthalate); depositing a fluid encapsulant into saidrecess, said encapsulant held in said recess by said film; andirradiating and curing said encapsulant.
 18. A patterned thin filmstructure, comprising: a thin film surface comprising at least onerecess; and an irradiated and cured encapsulant in the at least onerecess, wherein an upper surface of the encapsulant is planar.
 19. Astructure as recited in claim 18, wherein the encapsulant comprises atleast one of an irradiation activated gas-emitting material and anirradiation absorbing material.
 20. A structure as recited in claim 18,wherein the thin film surface further comprises at least one raisedportion.